As the use of local area networks (LAN's) and other computer networks proliferate, the problems of providing adequate security for the various resources available on the network become increasingly important. Such security includes protection against unauthorized use of the network by both individuals internal to an organization and those outside the organization, as well as preventing unauthorized use of various network resources by individuals granted only limited access to the network and/or to selected resources thereon. Thus, an individual may have the right to obtain information from one server on a network, but not from another server, or may be granted access to selected classes of information at a given server, for example, engineering data, but not other classes of data, for example, personnel records.
While various network security systems are available, they have suffered from a variety of limitations. The simpler systems provide security, generally by use of a numeric or alphanumeric personal identification number or code (PIN), to an individual machine or other resource on the system. An alphanumeric PIN (AN PIN) is sometimes also referred to as a password. In some instances, such PIN is passed in clear text over the network, making it vulnerable to unauthorized detection and misappropriation. Such systems also store the PIN at a user or client machine on the network (hereinafter client), meaning that someone misappropriating the client also gains access to the PIN, and thus access to the network. Such systems also frequently transmit sensitive data over the network in clear text form, making such data susceptible to unauthorized interception.
While more sophisticated systems exist which encrypt PINs for transmission and possibly for storage, and which also permit at least a selective encryption of data being transmitted on the line, such systems are frequently complicated to use. Even sophisticated systems such as the Kerberos authentication system developed at MIT, while normally requiring only a single log-on by a user, involve substantial amounts of data processing for all transactions, and basically require a server dedicated to the security function; and even sophisticated systems such as Kerberos are vulnerable if an intruder can successfully obtain a legitimate user's log in name and PIN.
Thus, a need exists for an improved integrated network security system which, while being easy to use, requiring only a single log-in by the user, while providing security utilizing at least two security factors. The three security factors generally utilized are something the user has (i.e. a card or token), something the user knows (i.e. a PIN) and something the user is (i.e. voice recognition, fingerprint, etc). The first two are the factors most commonly utilized. The system should also provide complete security for any numeric or alphanumeric PIN used. Such security should preferably prevent the detection of the PIN through decryption of an encrypted PIN surreptitiously intercepted on the network. Similarly, a PIN, even in encrypted form, should not be stored at a client when a client has been discourteously disconnected (removed from the network in an unauthorized fashion) or when the client is not in use. Such systems should also provide the capability of assuring that the client is not usable in any way, either itself or to access any resource on the network, when the client is to be locked (i.e. before a proper log on procedure has been completed and after a log off has occurred, while affording a capability of permitting limited use of the client at such time at the option of a network administrator.
All transmissions of sensitive information over the network should also be in encrypted form and access to various resources on the network, including servers and other clients, should be prevented until a proper log on has been completed at the client and should be fully controllable thereafter.